Variable size anode cap



26, 1959 E. c. KOWALEWSKI 3,464,053

VARIABLE SIZE ANODE CAP Filed Sept. 25, 1967 INVENTOR. Edward 6. Kowa/ewsk/ United States Patent US. Cl. 339-449 3 Claims ABSTRACT OF THE DISCLOSURE A variable size anode cap for use with vacuum tubes having anode terminals of difierent diameters.

This invention relates in general to vacuum tubes, and in particular, to vacuum tubes having its anode terminal at one end of the tube and the remainder of its terminals at the tube base. More particularly, this invention relates to an anode cap which may be varied in size for providing an electrical connection with differing diameter anode terminals.

Many vacuum tubes, particularly those operating under very high voltage conditions, utilize an anode terminal protruding from the top of the glass envelope whereas the remainder of the tube terminals are located at the lower end or base of the vacuum tube. In these vacuum tubes, the anode terminal is so located to eliminate electrical corona between it and the adjacent tube connections. While most anode terminals of the same tube type are of similar diameter, occasionally different manufacturers produce vacuum tubes having identical operating characteristics but with significantly diiferent diameter anode terminals. Since the tube operating characteristics are identical, television receiver manufacturers requiring vacuum tubes having the particular operating characteristics, or television servicemen replacing such tubes, can use tubes from either tube manufacturer, except for the anode terminal connection. This usually necessitates having anode caps, which are the female receptacle for the male anode terminal, of differing size, one size for large diameter anode terminals and another size for small diameter anode terminals. The requirement of two anode cap sizes is an inconvenience to the manufacturer who must contend with two inventory items, and must match the anode cap with the vacuum tube anode terminal currently used in production. Similarly, a serviceman servicing a product wherein such tubes are used must replace the anode cap should he substitute a new vacuum tube having a different diameter anode terminal than the tube' which he is replacing.

This invention obviates the above mentioned difficulties and inconveniences by providing an anode cap having an opening which may be varied in size to accommodate vacuum tube anode terminals of differing diameters. The means for varying the opening size are integral with the cap construction so that no extra parts are required. The anode cap is altered merely by changing an electrical contact member from one position to another.

Accordingly, the primary object of this invention is to provide an anode cap capable of accommodating vacuum tube anode terminals of differing diameters, and establishing an electrical connection therewith.

Another object of this invention is to provide an anode cap having an opening which may be altered in size without the necessity of additional parts for providing electrical connection with anode terminals of different diameters.

Other objects of this invention will become apparent upon an examination of the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an elevational view of a vacuum tube having a separate anode terminal and a variable size anode cap of the invention.

FIG. 2 is an enlarged, sectional view of the anode cap of the invention, and a portion of the vacuum tube, taken along line 22 of FIG.1.

FIG. 3 is an enlarged, bottom plan view of the anode cap and the anode terminal, taken along line 3-3 of FIG. 1.

FIG. 4 is a greatly enlarged perspective view of the movable contact element of the anode cap.

FIG. 5 is a plan view similar to FIG. 3, showing a modified form of the invention.

Referring to FIG. 1, there is shown a vacuum tube 10 comprising a glass envelope 11 having an anode terminal 12 at its upper end and a plurality of base terminals 14 at its lower end. The anode and base terminals are connected to various operative elements in the envelope, not shown. An anode cap, generally referred to by reference numeral 16, is provided for establishing electrical con tact between anode terminal 12 and an electrical circuit, not shown, in which the vacuum tube is to be employed.

Referring now to FIGS. 2, 3 and 4, the construction of the anode cap will be described in detail. The cap comprises an outer housing or shell 18 defining an opening or chamber 20 having dimensions slightly larger than the largest diameter anode terminal expected to be accommodated. The opening includes an arcuate wall 22 and a pair of slots 24 and 26 communicating therewith, although a greater number of slots could be provided to accommodate a greater number of different anode terminal diameters. The slots extend substantially parallel to each other and facingly oppose arcuate wall 22.

A resilient, electrically conductive contact member 30, best seen in perspective in FIG. 4 is provided for insertion into either of the slots 24 or 26. The slot into which contact member 30 would be inserted depends upon the diameter of the anode terminal. If the anode terminal has a small diameter, such as shown in FIGS. 2 and 3, the contact member is inserted into slot 24, thereby decreasing the effective size of the opening. If the anode terminal had a large diameter, the contact member would be inserted in slot 26. The contact member may be easily moved from one slot to another with the aid of a pair of narrow nose pliers.

The contact member is preferably fabricated of resilient steel sheet stock and has an overall rectangular shape with an arcuate cross-section. This arcuate cross-section is slightly distorted and tends to be straightened when the contact member is inserted in either slot. This distortion and the resilience of the member maintains it in position in the housing in spite of the frictional force from the anode cap being placed over or removed from the anode terminal. Contact member 30 also includes a pair of parallel ribs 34 which extend parallel to the axis of the anode terminal and maintain it centered in the cap opening. A high voltage lead 36 is electrically connected to contact member 30 to complete the anode cap assembly.

In an alternate embodiment, shown in FIG. 5, the contact member 30 is replaced with either a conductive or nonconductive movable member 40 which may be inserted in either of the slots provided. The electrical connection is maintained by a conductive insert 41 partially lining the interior of opening 20, and connected to a high voltage lead 36a.

In the above described invention, the effective opening size of an anode cap may be easily and rapidly altered to securely receive vacuum tube anode terminals of different diameters.

The embodiments of the invention in which an exelusive property or privilege is claimed are defined as follows:

1. A female receptacle for securely receiving variable size male members comprising: an electrically insulating housing defining an opening having interior dimensions greater than the exterior dimensions of the largest size male member to be accommodated; said housing defining a plurality of substantially parallel slots extending through the periphery of said opening; resilient means selectively positionable in any one of said slots for altering the effective interior dimensions of said opening, said resilient means comprising an arcuately shaped, electrically conductive member frictionally retained within any one of said slots for resisting the frictional force of said male member being removed from said opening; said conductive member establishing electrical contact with said male member, whereby said receptacle securely receives variable size male members.

2. The female receptacle as set forth in claim 1 wherein said opening is partially bounded by an arcuate side wall opposingly facing said conductive member; said conductive member including a pair of parallel ribs projecting toward said arcuate side wall for substantially centering said male' members within said opening.

3. An anode cap for establishing electrical contact with vacuum tube anode terminals of differing diameters comprising: an electrically insulating housing defining an anode terminal receiving opening of adequate interior dimensions to accommodate a large diameter anode teranimal; a movable, electrically conductive member fabricated from resilient material; said housing comprising a plurality of slots extending transversely through said opening, for selectively positioning said electrically conductive member within said opening to alter the effective size thereof, whereby said electrically conductive member is deformed by said anode terminal, for frictionally retaining said terminal in said opening.

References Cited UNITED STATES PATENTS 2,146,612 2/1939 Alden 339-258 X 2,147,160 2/ 1939 Hagist et al. 339272 2,228,138 1/1941 Larkin et al 339258 X 2,657,370 10/1953 Hobson -3 339-202 2,780,793 2/1957 Gambale 339--272 3,192,498 6/1965 Ruehlemann 339-33 3,208,032 9/1965 Tilesi 339-221 X RICHARD E. MOORE, Primary Examiner US. Cl. X.R. 339-221 

